Molding machine



Jan. 26, 1954 E. M. STANKEWICH 2,666,949

MOLDING MACHINE Filed Sept. 27, 1950 3 Sheets-Sheet 1 ArraeME) Jan. 26, 1954 E. M. STANKEWICH 2,666,949

MOLDING MACHINE Filed Sept. 27, 1950 3 Sheets-Sheet 2 F 2 60 K J 62 a /5. C- 52 LZww M ra /(Ema m/rzme.

Patented Jan. 26, 1954 UNI T ED I S FATEN'F Q F F-IE MOLDINGEMACHINE-r Edward MI StanIiewich; South? (lzone Park,:N". YT." Application september:27, 1950; summonses 7-Cl'aims. (Cl. 18f-527) The present invention relatestonovel molding; machines and more-particularlyto a type suitable;- for-. molding; plastic dentures and r, a variety. of;

other articlesof various materials;

An- .objecta of this inventioniistotprovide a. novel and improved molding, machine'whiche o only; brings molten substance; into the. mold; but also assures that the mold :cavity is packediull.

with; such substancet accomplish aprecision: cast pieceiree of voids.

Another object. hereof; is. toprovide a; novel ands-improved molding machine. of the character mentioned; havingra new; modeof operation :and t avoiding oxidation of the; molten; material,- so that it is possible touse a.substance such as nylon;

for molding of dentures which is heregiven as a particular example; Of course, the machine may be used for-themolding of other articles of various; materials as practiced-gin the, molding art geneerally.

A further object of this inventionisto provide;-

a molding machine of the nature; set forth, of novel and improved construction, which is; simple to operate, reasonable in cost to manufacture and'sefiicient in.carrying out thepurppses for which it is designed.

Otherlobjects andadvantages will beeomesap parent, as this disclosure proceeds;

To attain these objects, I have devised the presentrmachine which utilizes my novel process and: constructional features whereby the molten sub:- stance to fill the-mold is kept freevfrom the at-. mosphere; is drawn into the mold :cavity bythe action of vacuum, and then by the use of pressure upon an excess of molten material andupon that already in the mold cavity, Iaccomplish full packing of the mold cavity. As. a, component of. the machine I havega pumpmeans adaptableto.

beset to-workas a vacuum pump andthen when-g required'as a sort of force pump, as will be fully setforth, together withiwhole machine struc-- ture and its mode of operation.

In the accompanying drawings forming part "of this specification,.similar characters ofreference indicate-corresponding.partsinall the views.

Fig; 1 is a. front view of a machine embodying; the ,teachings :of this invention. Thisview is:

shown partly in section.

Fig.- 2 is a section taken at -lines42-2 in Fig; 1. Fig. 3 is a section. taken at lines 3-3.:in;Fig..- 1

Figs is afragmentaryfront view of the :motor= included in Fig. 3,:and associated components.

FigaS is a fragmentaryperspeotive J/lBW'ShOW-e ing pump, barrel valve and associated partsinclucled'inthe machine.

Figs.r 6-and =7 show-:valve actuating mechanism f in various '-positions during operation In a the. drawings, the numeral l 5; designates I generally -a-base showncomposed of the metal sec-. tions l6-.and.=:Il,- assembledin any suitablemanner with aheateinsulative piece e-between them. A pair of' ,fixedespaced rods l9 extend upwardly fromthenbase to serve 'aS-T track means for; a.- plate member 25, sli'clably mounted-on said :rocls. This plate memberfmayrbe provided with: handles 2 l so1 that it maybe slid-- along saidirods toholdr or make -accessiblefor'removal of a dental flask or other mold: structure denoted generallyby'the numeral- 22, fitted between the. base section Hi and said plate-.memberzfi in suitable recesses as.

shown. Atop theplate member 29;" is a, melting chamber. 23,2 which is positionedv between the rodsJB. The top ends-ofsaid rods are joined to a cross piece 24;- The socket ZSI -isof heat-insulative material, in-which; the bottom end of the rod extending irom thebasesection l his-fixed; Ma-

terial to be plasticized or melted and :thencast; in the cavity-26rof the mold 2 2, is admitted-into the-chamber.23,'througha chute tube 2"! provided with acovering capifi. The numeral-23 denotes a jacket in which suitable electrical heating coils 30 .arehoused.

The ;numeral 3! designates generally a plunger valve to controL-the fiow of molten material from I the melting chamber 23-into themold 22 through the upper gate-'32.. The numeraltddenotes ge erally-a barrel valve; whose duct 34, when in the positiomshown-along line A, connects the lower gate 35 -ofthemold--cavity with the cylinder 35.-

of a pump whose pistons-is 31,- while when at its -other; limit-position; said duct S i -connects said pump cylinder 36 with an outlet Siicontrolled byvthe hand. valve 39.: Theyendsof said duct are indicatedatcdfl and 41, which in theembodiment'shown are ninety degrees apart on the peripheral surface of the-barrel valve 33;,- Saidbarrelis ona shaft 42,

Aaframework-H; depending from the rear edgeof the;base=section l6; and heat-insulatedtherefrom-bymember 44 ,supports an electric motor 45 Whichis slidable ,thereon' between the track meme The: motor shaft 61 'is parallel to the. barrel-valveshaft142., A screwfis, journalledon.

bers iii.

ience,-;,one.= of these wsheaves zis denoted -by the Each. end. of.

3 numeral 50. On a pin 5|, sheave 50' carries 1 swingably mounted sheave 52'. On a pin 5|, sheave 553 carries the swingably mounted sheave 52. Extending centrally from the sheave 52 is the pin 53. Extending centrally from the sheave 52 is the pin 53. A compression spring 54', with its ends mounted on the elements 55' and 56', holds the sheaves 50' and 52' in non-concentric relation. A compression spring 54, with its ends mounted on the elements 55 and 55, holds the sheaves 5E and 52 in non-concentric relation. All parts carried on the motor shaft 41 are so arranged that pins 5| and 5| are in alignment, and also that pins 53 and 53 are in alignment.

A bar 51, forming a T shape with the piston rod 58, has a longitudinal slot '59, through which the pin 53 extends; said pin being slidable along said slot. The shaft 42 carries a crank 60, whose pin 6| extends into and is free to slide in a slot 62 at an end of the connecting bar 63, whose other end is pivotally mounted on the pin 53'. One end of a stressed tension coil spring 64 is connected to the crank Gil at a point 65 which is intermediate the shaft 42 and the crank pin 8 l. The other end of this spring 64 is connected to the framepiece 43 at a point t5 such that when the barrel valve 33 is midway in its travel between its remote positions mentioned, the line of points 85 and 5t, intersects the axis line of shaft 42.

The conical bottom end of the valve rod '8'! of the plunger valve 3!, normally rests on valve seat 68, cutting oil thereby communication from the heating chamber 23 to the upper gate 32. The numeral 69 designates a bridge-piece mounted atop the heating chamber 23, for threadedly supporting a bushing 70 which serves as a hearing from the sliding movement of the valve rod 61. A stressed compression spring 'il about said rod, is positioned between and against the bushings flange and a collar 72 fixed on said rod 6?. Near ceiling region interior chamber 23, said valve rod carries the fixed collar 73 which is attached to a thin springy metal plate '14 forming an hermetically sealed chamber 15. A vacuum pump not shown, is arranged to exhaust air from the chambers 23 and 15, by connection at 16, through the branches l! and 18 respectively connected by suitable lengths of flexible tubing 19 and 80, to the openings BI and 82 of said respective chambers. Control of vacuum action is accomplished by means of the hand-operated valves 83 and B4 interposed in said branches respectively. The numerals 85 indicate bearing members which are spaced as at 86, to permit molten substance to flow from the melting chamber 23 into the upper gate 32, when the valve 3| is in open condition as shown in Fig. 1.

It is to be noted that when the intensity of vacuum effected in chamber l5 exceeds that in chamber 23, the springy plate I4 will be flexed upward whereupon the valve 3! will be in open condition. Equalizing the degree of vacuum in both these chambers, will cause said valve 3| to close. Also to be noted is that action of piston 37 in cylinder 36 while the barrel valve 33 is permitted to oscillate, is that of a vacuum pump exhausting the mold cavity 26. During such pump operation, when the intensity of vacuum effected in the mold cavity 28, exceeds that in chamber 23, and whereupon the valve 3| is open, molten substance from the chamber 23 will be forcibly drawn into the mold cavity.

It is evident that the position of the motor determines the distance between the motor shaft 4'! and the pin 53, and hence the length of stroke of the piston 31. Said motor is initially positioned by manipulation of handle 49, to permit said piston 31 its longest stroke, measured as twice the distance the axes of the motor shaft 41 and the pin 53. The spring 54 is of sufficient stiffness to maintain any desired amount of overlapping of the sheaves it is associated with. While the motor is operating, manipulation of handle 49 to shift the motor towards the left in Fi 3, will cause the motor shaft to come into axial alignment with the pins 53 and 53', whereupon piston 31, for its very last movement will halt at the cylinder end nearest the barrel valve 33, because the piston rod 58 is moved towards the left. Also, simultaneously, because the connecting member 63 is moved towards the left, the barrel valve 33 will halt with its duct 34 in position along line A.

The flask 22 may be of two dished halves 22 and 22", provided respectively with the upper gate 32 and the lower gate 35, and held detachably together in any suitable fashion known in the art after impressions are made in plaster of Paris fills 8'! and 87' to form the mold cavity 26, which if for a dental plate for instance, may have teeth 88 inset, as is well known in the dental art. The casting of a dental plate is taken as an example, because this machine is adapted for making the plate of nylon. As mentioned, nylon need be worked to the exclusion of air in order to avoid oxidation. Since vacuum may be attained in both the melting chamber 23 and in the mold cavity 26, the prescribed condition is accomplished. If the nature of the substance worked with needs no assurance against oxidation, valve 83 is left closed and the chute tube 2'! may be left open during casting operation. In the statement of operation now to be given, use of nylon as the casting material is assumed. Also I shall assume that the mold structure is in condition to be set in the machine as shown in Fig. 1.

To set the machine for operation, plate 20 is raised and the mould structure 22 is set in its receiving recess atop the base section l6. Said plate is now lowered to set on the mold structure; receiving the top of same in a suitable recess provided for such purpose in the underside of said plate 20. Electric current is supplied to the heater coil 89 imbedded in the base section I 6, so that molten substance issuing from the heating chamber 23, into the flask 22, from which some will come through the barrel valve 33 and into the cylinder 36, shall remain fluid. The vacuum pump connected to 16 is actuated. Valves 83 and 84 are closed. Valve 39 is opened slightly. The plunger valve 3| is in closed condition. Heater coils 3! are supplied with electric current. A suflficient quantity of nylon pellets or granules are thrown into the melting chamber 23 through the chute tube 21 and said chamber hermetically sealed upon mounting the cap 28.

Handle 49 is now turned to shift the motor 45 to its position along tracks 45, so that the distance between the axes of the motor shaft 41 and the pin 53 is such that the barrel valve 33 will oscillate whereby its duct 34, at the limits of movement will be at the position shown in Fig. 1 along line A and at the position where said duct connects passage 35 with the cylinder 36, respectively. The assembly illustrated is such, that when piston 81 is at the cylinder end nearest the barrel valve 33, the duct 34 of said valve will be along line A.

Motor 45 is now actuated and let run c0ntinunaemia;-

s y: Valve. 83*; is opened to create; vacuum; in the melting: chamber. Rotationof motor 45 will cause the barrel' valve 33 to oscillate and the piston 37' to reciprocate. During travel of'said piston to the right in Fig. '1'; the; air from the mold; cavity 25 will be withdrawn through duct 34f atpositionA- and-thenceintofthe cylinder 3 51% Air-in the said-cylinder-behind thepiston; is ex polled by piston movement through the hole 90. Upon return movement of the piston 31, the valve duct 34 is in position connecting the cylinder 36 with the drip pipe 38, and hence any air in front of the piston, will be expelled through 38. It is therefore apparent that molten substance whether within the melting chamber 23 or within the mold cavity 26, or in the duct 34 while the barrel valve is at position A, or if drawn into the cylinder 36, is always free from the influence of air, eliminating the possibility of any oxidation to occur.

After proper lapse of time to permit the nylon substance to melt, valve 84 is operated to create a greater degree of vacuum in chamber than exists in the melding chamber 23, whereupon valve rod will be lifted due to the upward flexing of the diaphragm 14, to open the plunger valve 3!. Molten substance will be drawn into the mold cavity 26 from the meltin chamber 23, by the vacuum action effected by operation of the piston 3?; operation being such that the degree of vacuum existing in the said cavity exceeds that existing in the melting chamber. As the mold cavity fills, some of the nylon substance Will be drawn into the cylinder 35, and depending upon duct position, will be forced back into the mold cavity 26, or forced out through the drip at 38. After suitable lapse of time for the entire mold cavity to be filled, valve 84 is closed, valve 83 is opened fully, whereupon plunger valve 3| closes, and simultaneously with these manipulations or nearly so, handle 49 is turned to shift the motor 35 to a position where its shaft 41 is in axial alignment with the pins 53 and 53', whereupon piston 31 coming to end of cylinder 35, nearest the barrel valve 33 Whose duct 34 is now along position of line A, acts as a force pump and forces molten substance from cylinder 36 to pack the mold cavity 26 and thus insure a precision casting. The action of the piston 31 is to feed molten substance into the mold cavity by drawing it therein by vacuum, and then packing the mold cavity by pressure. Immediately before or after the mentioned manual operations, the current supply is out off to the heating coils 33 and 89, and to the motor 45. After all heated parts have cooled sufficiently, the flask 22 is removed, and the finished casting taken from the mold.

It is advisable that the barrel valve 33, shall move from one to the other of its limit positions, faster than would be accomplished by movement of its controlling crank pin 53. Referring to Figs. 6 and 7, it is to be noted that in each direction of movement of the connecting arm 63, as soon as the member 60 is shifted beyond the position where points 65, 42 and 66 are in alignment, the stressed spring 64 will hasten movement of said member 60 to the limit position it is approaching, as is permitted by the slot 62. This means to hasten movement is well known, and therefore requires no further explanation as it is well understood by those versed in the machine art.

Other plastics or metals may be used for easting articles of all kinds with this machine. The

struction, mast. bfia Sfid' for;raisin tlowerine andi securing ,theplategZfi.

Thisinvention; is. capahleeot rari usrfonrnsiands.

applications without departing from theaessehn.

tial featur s herein disclosed-.1. Itiisltherefe e ntendeds andi des redi that l the embodiment: i luse t at d s a be deemedzillustrativeandianottna-e strictive andi that; the\ patent; shall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific description herein, to indicate the scope of this invention.

I claim:

1. In a molding machine of the character described, the combination of a melting chamber, a mold having a mold cavity with an entrance passage thereto and an exit passage therefrom; said entrance passage being communicative with the melting chamber to receive molten substance therefrom, a valve for controlling the fiow of molten material from the melting chamber into said entrance passage, a cylinder having a piston movable therein, a valve means comprising a stator member having three ports; the first being communicative with the exit passage from the mold cavity, the second being communicative with the cylinder and the third being a discharge orifice, and a movable valve member carried by the stator member; said movable valve member having a duct which at a first position of the movable valve member, connects the first and second ports of the valve stator, and at a second position of the movable valve member, connects the second and third ports of the valve stator. means to oscillate the movable valve member from one of said positions to the other, a means to reciprocate the piston within the cylinder, whereby said piston is at the second port every time the movable valve member is at the said first position, and away from said second port every time the movable valve member is at saidsecond position and operator-controlled means to halt the movable valve member at said first position.

2. A machine as defined in claim 1, including means to accelerate movement of the movable valve member from its respective positions after each commencement of a reversal of movement of the piston within the cylinder.

3. A machine as defined in claim 1, including means to heat the piston, cylinder, valve stator, movable valve member and the mold.

4. A machine as defined in claim 1, wherein the cylinder and the valve stator member serve as a base to support the mold.

5. A machine as defined in claim 4, including a base adapted to support a mold, provided with a duct connecting the exit passage of the mold cavity with the first port in the valve stator when the mold is set on the base, and including a plate member adapted to be set atop the mold; the melting chamber being mounted atop said plate; said plate having an opening therethrough, communicative with the entrance passage to the mold cavity and the melting chamber; the valve controlling the flow of molten substance from said melting chamber into the entrance passage to the mold cavity, including a slidably mounted rod, normally closing the opening in the plate member, a springy membrane member secured to said rod, another chamber; said membrane closing both said other chamber and the melting chamber hermetically, and means to alter the References Cited in the flle of this patent pressure in said other chamber to operate said TEN rod to control the flow of molten substance from UNITED STATES PA TS the melting chamber into the mold cavity. Number Name Date 6. A machine as defined in claim 5, including 5 791548 Rlctfards June 1905 means to alter the pressure within the melting 2,269,953 Morm et a1 1942 chamben 2,359,013 Tucker Sept. 26, 1944 2,501,329 Hall Mar. 21, 1950 7. A machine as defined in claim 6, wherein each of the means for altering the pressure establishes a vacuum condition. 10

EDWARD M. STANKEWICH. 

